1. Field of the Invention
The present invention relates generally to a beamforming antenna system. More specifically, the present invention relates to a beamforming antenna system employing a blind dual error antenna diversity (DEAD) algorithm. Corresponding methods are also disclosed.
2. Discussion of Related Art
Adaptive antenna array technology is being explored for applicability in the domains of wireless communications, sonar, and Acoustic Echo Cancellation (AEC), to name but a few. In land based communications networks, an adaptive antenna array permits more users-per-cell by allowing frequency reuse within the cell. It will be noted that this is achieved primarily by adaptively directing the beam patterns of the receiving and transmitting antennae. Few researchers have considered the applicability of adaptive antenna array technology to the problem of poor signal reception of terrestrial DTV by an indoor antenna.
The ATSC standard set forth by the Advanced Television Systems Committee in the document entitled “ATSC Digital Television Standard” (Document A53, Sep. 16, 1995), for terrestrial Digital TV in the United States requires transmission of an MPEG bit stream of 19.28 Mbps over a bandwidth of 6 MHz at a symbol rate of 10.76 MHz in the VHF and UHF carrier frequency range. The modulation scheme used is a single carrier 8 level Vestigial Sideband (VSB) modulation scheme.
The Advanced Television Standards Committee (ATSC) terrestrial Digital Television (DTV) receivers on the market today are not able to provide reliable reception using an indoor antenna. This is due to low Signal to Noise Ratio (SNR) and multiple close-in multipaths that are caused by the indoor environment. In the indoor environment, the desired signal is attenuated and channel distortion is increased due to nearby reflecting surfaces and significant short reflections from multipath in the home. People moving in the home add dynamic aspects to the multipath. Current state of the art receiver equalization architectures have a single antenna and use a Decision Feedback Equalizer (DFE) to compensate for the channel impairments. It will be appreciated that current equalizer technology only takes temporal equalization into effect.
What is needed is a beamforming structure that produces a narrow, high gain, receiving beam in the direction of the desired signal. Moreover, what is needed is a beamforming structure that produces a narrow, high gain, receiving beam while attenuating the surrounding channel distortion. Furthermore, a beamforming structure implementing a Blind Dual Error Antenna Diversity (DEAD) Algorithm would be extremely desirable, particularly when the DEAD algorithm can be implemented at little additional cost.